Re: [PATCH 4.14 023/159] mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y

[Baoquan He]

On 02/07/18 at 08:17pm, Dou Liyang wrote:
> Hi Baoquan,
> 
> At 02/07/2018 08:08 PM, Baoquan He wrote:
> > On 02/07/18 at 08:00pm, Dou Liyang wrote:
> > > Hi Kirill,Mike
> > > 
> > > At 02/07/2018 06:45 PM, Mike Galbraith wrote:
> > > > On Wed, 2018-02-07 at 13:41 +0300, Kirill A. Shutemov wrote:
> > > > > On Wed, Feb 07, 2018 at 05:25:05PM +0800, Dou Liyang wrote:
> > > > > > Hi All,
> > > > > > 
> > > > > > I met the makedumpfile failed in the upstream kernel which contained
> > > > > > this patch. Did I missed something else?
> > > > > 
> > > > > None I'm aware of.
> > > > > 
> > > > > Is there a reason to suspect that the issue is related to the bug this patch
> > > > > fixed?
> > > > 
> > > 
> > > I did a contrastive test by my colleagues Indoh's suggestion.
> > > 
> > > Revert your two commits:
> > > 
> > > commit 83e3c48729d9ebb7af5a31a504f3fd6aff0348c4
> > > Author: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> > > Date:   Fri Sep 29 17:08:16 2017 +0300
> > > 
> > > commit 629a359bdb0e0652a8227b4ff3125431995fec6e
> > > Author: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> > > Date:   Tue Nov 7 11:33:37 2017 +0300
> > > 
> > > ...and keep others unchanged, the makedumpfile works well.
> > > 
> > > > Still works fine for me with .today.  Box is only 16GB desktop box though.
> > > > 
> > > Btw, In the upstream kernel which contained this patch, I did two tests:
> > > 
> > >   1) use the makedumpfile as core_collector in /etc/kdump.conf, then
> > > trigger the process of kdump by echo 1 >/proc/sysrq-trigger, the
> > > makedumpfile works well and I can get the vmcore file.
> > > 
> > >       ......It is OK
> > > 
> > >   2) use cp as core_collector, do the same operation to get the vmcore file.
> > > then use makedumpfile to do like above:
> > > 
> > >      [douly@localhost code]$ ./makedumpfile -d 31 --message-level 31 -x
> > > vmlinux_4.15+ vmcore_4.15+_from_cp_command vmcore_4.15+
> > 
> > Oh, then please ignore my previous comment. Adding '-D' can give more
> > debugging message.
> 
> I added '-D', Just like before, no more debugging message:
> 
> BTW, I use crash to analyze the vmcore file created by 'cp' command.
> 
>    ./crash ../makedumpfile/code/vmcore_4.15+_from_cp_command
> ../makedumpfile/code/vmlinux_4.15+
> 
> the crash works well, It's so interesting.
> 
> Thanks,
> 	dou.
> 
> The debugging message with '-D':

And what's the debugging printing when trigger crash by sysrq?

> 
> [douly@localhost code]$ ./makedumpfile -D -d 31 --message-level 31 -x
> vmlinux_4.15+  vmcore_4.15+_from_cp_command vmcore_4.15+
> sadump: does not have partition header
> sadump: read dump device as unknown format
> sadump: unknown format
> LOAD (0)
>   phys_start : 1000000
>   phys_end   : 2a86000
>   virt_start : ffffffff81000000
>   virt_end   : ffffffff82a86000
> LOAD (1)
>   phys_start : 1000
>   phys_end   : 9fc00
>   virt_start : ffff880000001000
>   virt_end   : ffff88000009fc00
> LOAD (2)
>   phys_start : 100000
>   phys_end   : 13000000
>   virt_start : ffff880000100000
>   virt_end   : ffff880013000000
> LOAD (3)
>   phys_start : 33000000
>   phys_end   : 7ffd7000
>   virt_start : ffff880033000000
>   virt_end   : ffff88007ffd7000
> Linux kdump
> page_size    : 4096
> 
> max_mapnr    : 7ffd7
> 
> Buffer size for the cyclic mode: 131061
> The kernel version is not supported.
> The makedumpfile operation may be incomplete.
> 
> num of NODEs : 1
> 
> 
> Memory type  : SPARSEMEM_EX
> 
> mem_map (0)
>   mem_map    : ffff88007ff26000
>   pfn_start  : 0
>   pfn_end    : 8000
> mem_map (1)
>   mem_map    : 0
>   pfn_start  : 8000
>   pfn_end    : 10000
> mem_map (2)
>   mem_map    : 0
>   pfn_start  : 10000
>   pfn_end    : 18000
> mem_map (3)
>   mem_map    : 0
>   pfn_start  : 18000
>   pfn_end    : 20000
> mem_map (4)
>   mem_map    : 0
>   pfn_start  : 20000
>   pfn_end    : 28000
> mem_map (5)
>   mem_map    : 0
>   pfn_start  : 28000
>   pfn_end    : 30000
> mem_map (6)
>   mem_map    : 0
>   pfn_start  : 30000
>   pfn_end    : 38000
> mem_map (7)
>   mem_map    : 0
>   pfn_start  : 38000
>   pfn_end    : 40000
> mem_map (8)
>   mem_map    : 0
>   pfn_start  : 40000
>   pfn_end    : 48000
> mem_map (9)
>   mem_map    : 0
>   pfn_start  : 48000
>   pfn_end    : 50000
> mem_map (10)
>   mem_map    : 0
>   pfn_start  : 50000
>   pfn_end    : 58000
> mem_map (11)
>   mem_map    : 0
>   pfn_start  : 58000
>   pfn_end    : 60000
> mem_map (12)
>   mem_map    : 0
>   pfn_start  : 60000
>   pfn_end    : 68000
> mem_map (13)
>   mem_map    : 0
>   pfn_start  : 68000
>   pfn_end    : 70000
> mem_map (14)
>   mem_map    : 0
>   pfn_start  : 70000
>   pfn_end    : 78000
> mem_map (15)
>   mem_map    : 0
>   pfn_start  : 78000
>   pfn_end    : 7ffd7
> mmap() is available on the kernel.
> Checking for memory holes                         : [100.0 %] |         STEP
> [Checking for memory holes  ] : 0.000014 seconds
> __vtop4_x86_64: Can't get a valid pte.
> readmem: Can't convert a virtual address(ffff88007ffd7000) to physical
> address.
> readmem: type_addr: 0, addr:ffff88007ffd7000, size:32768
> __exclude_unnecessary_pages: Can't read the buffer of struct page.
> create_2nd_bitmap: Can't exclude unnecessary pages.
> Checking for memory holes                         : [100.0 %] \         STEP
> [Checking for memory holes  ] : 0.000006 seconds
> Checking for memory holes                         : [100.0 %] -         STEP
> [Checking for memory holes  ] : 0.000004 seconds
> __vtop4_x86_64: Can't get a valid pte.
> readmem: Can't convert a virtual address(ffff88007ffd7000) to physical
> address.
> readmem: type_addr: 0, addr:ffff88007ffd7000, size:32768
> __exclude_unnecessary_pages: Can't read the buffer of struct page.
> create_2nd_bitmap: Can't exclude unnecessary pages.
> 
> makedumpfile Failed.
> 
> > 
> > > 
> > >      ......It causes makedumpfile failed.
> > > 
> > > 
> > > Thanks,
> > > 	dou.
> > > 
> > > > 	-Mike
> > > > 
> > > > 
> > > > 
> > > 
> > > 
> > 
> > 
> > 
> 
>